Index: mlir/include/mlir/IR/Block.h
===================================================================
--- mlir/include/mlir/IR/Block.h
+++ mlir/include/mlir/IR/Block.h
@@ -13,6 +13,7 @@
 #ifndef MLIR_IR_BLOCK_H
 #define MLIR_IR_BLOCK_H
 
+#include "mlir/IR/PrinterHook.h"
 #include "mlir/IR/BlockSupport.h"
 #include "mlir/IR/Visitors.h"
 
@@ -336,7 +337,7 @@
   }
 
   void print(raw_ostream &os);
-  void print(raw_ostream &os, AsmState &state);
+  void print(raw_ostream &os, AsmState &state, PrinterHookBase *hook = nullptr);
   void dump();
 
   /// Print out the name of the block without printing its body.
Index: mlir/include/mlir/IR/Operation.h
===================================================================
--- mlir/include/mlir/IR/Operation.h
+++ mlir/include/mlir/IR/Operation.h
@@ -241,7 +241,7 @@
   bool isBeforeInBlock(Operation *other);
 
   void print(raw_ostream &os, const OpPrintingFlags &flags = llvm::None);
-  void print(raw_ostream &os, AsmState &state);
+  void print(raw_ostream &os, AsmState &state, PrinterHookBase *hook = nullptr);
   void dump();
 
   //===--------------------------------------------------------------------===//
Index: mlir/include/mlir/IR/PrinterHook.h
===================================================================
--- /dev/null
+++ mlir/include/mlir/IR/PrinterHook.h
@@ -0,0 +1,40 @@
+//===- PrinterHook.h - Printer hook for annotations -------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the base class of Annotation printer hooks
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_IR_PRINTER_HOOK_H
+#define MLIR_IR_PRINTER_HOOK_H
+
+#include "mlir/Support/LLVM.h"
+
+namespace mlir {
+
+class Operation;
+class Block;
+
+/// Printer Hook to add annotations before an after IR constructs.
+/// It allows analysis to print there results directly within the IR making it
+/// easier for human to read analysis results.
+class PrinterHookBase {
+public:
+  /// Every annotations should be a self-contained comment. so it must start
+  /// with "//" (maybe after indenting) and finish with a newline. otherwise it
+  /// will likely not be possible to parse the generated IR.
+  virtual void printCommentBeforeOp(Operation *op, raw_ostream &os,
+                                    unsigned currentIndent) = 0;
+  virtual void printCommentBeforeBlock(Block *block, raw_ostream &os,
+                                       unsigned currentIndent) = 0;
+  virtual ~PrinterHookBase();
+};
+
+} // namespace mlir
+
+#endif
Index: mlir/lib/IR/AsmPrinter.cpp
===================================================================
--- mlir/lib/IR/AsmPrinter.cpp
+++ mlir/lib/IR/AsmPrinter.cpp
@@ -25,6 +25,7 @@
 #include "mlir/IR/MLIRContext.h"
 #include "mlir/IR/OpImplementation.h"
 #include "mlir/IR/Operation.h"
+#include "mlir/IR/PrinterHook.h"
 #include "mlir/IR/SubElementInterfaces.h"
 #include "mlir/IR/Verifier.h"
 #include "llvm/ADT/APFloat.h"
@@ -2718,8 +2719,10 @@
   using Impl = AsmPrinter::Impl;
   using Impl::printType;
 
-  explicit OperationPrinter(raw_ostream &os, AsmStateImpl &state)
-      : Impl(os, state), OpAsmPrinter(static_cast<Impl &>(*this)) {}
+  explicit OperationPrinter(raw_ostream &os, AsmStateImpl &state,
+                            PrinterHookBase *hook = nullptr)
+      : Impl(os, state), OpAsmPrinter(static_cast<Impl &>(*this)),
+        annotationHook(hook) {}
 
   /// Print the given top-level operation.
   void printTopLevelOperation(Operation *op);
@@ -2905,6 +2908,9 @@
 
   // This is the current indentation level for nested structures.
   unsigned currentIndent = 0;
+
+  /// Hook to print annotations before or after blocks and operations
+  PrinterHookBase *annotationHook;
 };
 } // namespace
 
@@ -3010,6 +3016,9 @@
 }
 
 void OperationPrinter::printFullOpWithIndentAndLoc(Operation *op) {
+  if (annotationHook)
+    annotationHook->printCommentBeforeOp(op, os, currentIndent);
+
   // Track the location of this operation.
   state.registerOperationLocation(op, newLine.curLine, currentIndent);
 
@@ -3194,6 +3203,10 @@
 
 void OperationPrinter::print(Block *block, bool printBlockArgs,
                              bool printBlockTerminator) {
+
+  if (annotationHook)
+    annotationHook->printCommentBeforeBlock(block, os, currentIndent);
+
   // Print the block label and argument list if requested.
   if (printBlockArgs) {
     os.indent(currentIndent);
@@ -3491,8 +3504,8 @@
   AsmState state(op, printerFlags);
   print(os, state);
 }
-void Operation::print(raw_ostream &os, AsmState &state) {
-  OperationPrinter printer(os, state.getImpl());
+void Operation::print(raw_ostream &os, AsmState &state, PrinterHookBase *hook) {
+  OperationPrinter printer(os, state.getImpl(), hook);
   if (!getParent() && !state.getPrinterFlags().shouldUseLocalScope()) {
     state.getImpl().initializeAliases(this);
     printer.printTopLevelOperation(this);
@@ -3519,8 +3532,8 @@
   AsmState state(parentOp);
   print(os, state);
 }
-void Block::print(raw_ostream &os, AsmState &state) {
-  OperationPrinter(os, state.getImpl()).print(this);
+void Block::print(raw_ostream &os, AsmState &state, PrinterHookBase *hook) {
+  OperationPrinter(os, state.getImpl(), hook).print(this);
 }
 
 void Block::dump() { print(llvm::errs()); }
@@ -3539,3 +3552,5 @@
   OperationPrinter printer(os, state.getImpl());
   printer.printBlockName(this);
 }
+
+PrinterHookBase::~PrinterHookBase() = default;